1. Field of the Invention
The present invention relates to an arm mechanism, and a vacuum robot provided with the same.
2. Discussion of the Background
For example, Japanese Patent No. 3881579 and the like disclose a configuration of an arm of a robot for transferring a substrate. According to the configuration disclosed in Japanese Patent No. 3881579, in order to actuate an arm and a hand of a robot, transmission mechanisms, such as a motor, a decelerator and a timing belt, are placed inside the arm. Occasionally, such a robot is installed in a vacuum container brought into a pressure-reduced state from an atmospheric state, and is used for transfer of a substrate such as a wafer or a glass. The robot, which is installed in the vacuum container, is referred to as a vacuum robot. The vacuum robot causes no damage to the vacuum environment in the vacuum container, and therefore operates while isolating the vacuum environment from the atmospheric environment.
Occasionally, a processing chamber for the substrate is connected around the vacuum container in which the vacuum robot is installed. In some cases, processes are carried out at high temperature in the processing chamber. In the processing chamber, the processes such as etching and CVD are carried out at high temperature under a pressure-reduced environment. For the processes, the vacuum robot needs to transfer the substrate while keeping the high temperature. In such a case, the vacuum container, in which the vacuum robot is installed, undergoes a rise in temperature due to the heat from the substrate and the heat from the processing chamber. The temperature of the substrate itself occasionally rises to a high temperature of 100° C. or more. As one of countermeasures against the problems of heat, for example, JP 2007-015023 A discloses such a solution that a link configuration is adopted for an arm itself.